Piston ring



I. W. FORD.-

PISTON RING. APPLICATION FILED .IA'N. 27,192]! I Patented Mar. 28,1922.

- UNITED STATES PATENT @FFt-i" JOHN W. FORIKQF HILLSBORO, ILLINOIS, ASSIGNOR, BY MESNE ASf'sIGltl'lY-SEBW'EL f ll SPYRGSHAL MANUFACTURING COMPANY, OF ST, LOUIS, MISSQ'UEI, A URI1- RATION OF MISSOURI.

PISTON RING.

Specification of Letters Patent. Patenf Li l 28 1 Application filed January 27, 1921. Serial No. 440,379.

To all whom it may concern:

Be it known that L'JOHN \V. Form, a citizen of the United States, and residing at Hillsboro, Illinois, have invented the new and useful Improvement in 'Piston Rings, of which the following; is a specificat1on.

This invention relates to piston rings, and more particularly to. iston rings of the long lap type, in which the ends overlap for a major or extended part of the ring circumference,- as distinguished from the short lap vtype in which the ends overlap for a short distance or only sufficiently to form the joint.

The superiority of the long lap piston ring over the short lap type is primarily due to the fact that the former has a substantially uniform bearing against the cylinder walls, even though its. thickness may be uniform. As distinguished from the multi-piece ring, the one-piece long lap ring not only avoids the breaking up of the ring structure into a series of pieces, but the long lap ring does in tact give a better bearing action against the cylinder walls than the Inulti-pieee ring. It must be kept in mind that as far as leakage is concerned, it is of less importance to have a sealed joint between the ends than to have a bearing on the cylinder walls throughout the circumference of the ring. Moreover, piston rings are constructed almost universally of cast iron in order to secure the desired wearing surface although cast iron of itself has a low resilience There are two types of long lap piston rings. In one type the ends. overlap for about one-half of the ring! circumference so that the .tips are at diametrically opposite ends. This, however; makes onehalf of the ring stiff while the other half is weak. Accordingly not only will the pressure applied to the cylinder walls be ununiform, although it is more uniform than the short lap type, but the effect of this construction is that the hearing will really frce'spaces through which leakage can take place. Furthermore, in view of the fact that the tips are at diametrically opposite points and at the ends of a diameter, these tips have a tendency to project radially as be-at diametrically opposite points, leaving to take place. In another type oi ring; the ends overlap for nearly the entire ringcumferenee. This, however, leaves a small amount of metal at the center of the ring: so that the stillness otthe ring is reduced to such an extent that suflicient hearing on the cylinder walls cannot'be ohm (it One of the objects of this therefore, is to provide a long ring which is so eonstruotec maximum uniform bearing'on walls along the entire ring (fl"Hll with maximum resiliency and Further objects will appear detail description taken. in conn the companys drawing, in wh ch .1

Figure 1 is a perspective I of a 1." blank embodying this invention;

Figure 2 is a similar view show ends inverted to overlap so as to within a recess in the other; Figure 3 is a side elev "on; an 1 Figure 4 is an edge elevation of ti pleted ring.

The ring embodying this inventior be made in various Ways, and in race with various methods, but in lie understand the construction, one methods of making it will be briefly described.

Referring to Figure l, the ring a center part or body 1 provided 2 and 3,v which ends are recessed taper from the body portion 1 to the tips and thelrecesses are tapered corresponding ly. The blank may he formed by casting or machining, and the faces otthe recesses 4 and 5 as well as the shoulders 6 and 7 and the tips 8 and 9 are accurately formed so asto present the proper surface. The ends 2 and 3 are new inverted as shown in Figure 2, thereby causing one to lie within a recess in the other and in mutual engagement throughout their parting. The ring blank is then dressed laterally and circumferentially to the proper diameter and width so that when the ring is placed on the piston and in the cylinder, the ring will be contracted to the vdiameter of the cylinder at which time the tipswill pram tically engage the shoulders. It is, of course, understood that dressing the ring circumference, it is contracted to its proper diameter so as to present a proper 

